Adult Refsum disease, otherwise known as ARD, is a type of leukodystrophy--a group of genetic diseases which damage the white matter of the brain and can interfere with movements. It is also called Phytanic Acid Storage Disease, or Heredopathia Atactica Polyneuritiformis. People who have this dis
ease do not have an enzyme that breaks down phytanic acid, which is in most foods. Because the acid cannot be broken down by their bodies, toxic levels of it build up in the brain, blood, and other tissues.
Inheritance Pattern:
This disease is inherited through the autosomal recessive pattern, in which both copies of the gene in each cell have mutations. The parents each have a mutated gene, although they are generally only carriers and do not have the disease themselves. Most of the cases of Refsum disease comes from mutations in the PHYH gene. The PHYH gene is located on the short arm of the chromosome 10, at position 13, which is shown here.
Chromosome 10
The molecular location of the exact gene is on base pairs 13,319,795 to 13,342,129. The normal function of this gene is to provide instructions for making an enzyme called phytanoyl-coenzyme A (CoA) hydroxylase. The enzyme is what makes the peroxisomes--sac-like compartments that break down substances like fatty acids and toxic compounds--able to work. Phytanic acid is one of the fatty acids that the enzyme helps break down. Without that enzyme, the phytanic acid found mostly in meat and dairy food products, cannot be broken down and so it builds up in muscles and tissue.
Symptoms:
There are many symptoms of this disease, even though the disease itself is not very common, with less than 200,000 known cases as of 2010. Symptoms of Refsum's normally don't appear until the person reaches 20, although all symptoms might not appear until age 50. Initially, the symptoms start with retinitis pigmentosa--when the retina in your eye starts to degenerate, affecting night vision and peripheral vision, and can lead to blindness. Then peripheral polyneuropathy may occur--a dysfunction of the nerves outs
Icthyosis
ide your spinal cord, which can cause
The fourth toe of people who have Refsum's is significantly higher up on the foot than the rest of the toes.
numbness, weakness, burning pain, and loss of reflexes. Other symptoms include deafness and cerebellar ataxia--wobbliness and incoordination. Anosmia is another common symptom, which is the loss of your sense of smell, along with papillary abnormalities (pupil abnormalities), nystagmus (rapid involuntary eye movements), icthyosis (scaliness of skin), and epiphyseal dysplasia (shortened or malformed limbs).
Treatment/Prognosis:
The prognosis of this disease varies very dramatically. There is a dietary regimen (consuming less than 10 mg/day of foods high in phytanic acid) that can cause the nerve response to improve, and cause the neurological symptoms to stop. Weakness and scaliness can also improve. The diet avoids beef, lamb, milk, full cream, butter, and cheese--all foods with a high concentration of phytanic acid. It is important to try and maintain your weight when you have this disease, because loss of weight can release stored aid that was in fat tissues, causing the symptoms to become worse. Before the dietary regimen was established, more than half of patients died before they turned 30. Now, very few patients have died so young. Plasmapheresis (replacement of plasma) is another treatment that may help ease symptoms. Without treatment, ARD can cause death because of heartbeat abnormalities.
There are a few support groups for Refsum's disease, the most popular being in Illinois. The contact information is listed below.
Refsum's disease is considered a rare disease by the Office of Rare Diseases of the National Institutes of Health, because it affects less than 200,000 people in the US. Orphanet--the European version of ORDNIH--considers this disease rare because only one out of 2,000 people have it. There is not a certain group of people that are more susceptable to it, although Refsum's is a recessive autosomal disease.
Refsum Disease
Paige KnappDescription of Disease:
Adult Refsum disease, otherwise known as ARD, is a type of leukodystrophy--a group of genetic diseases which damage the white matter of the brain and can interfere with movements. It is also called Phytanic Acid Storage Disease, or Heredopathia Atactica Polyneuritiformis. People who have this dis
ease do not have an enzyme that breaks down phytanic acid, which is in most foods. Because the acid cannot be broken down by their bodies, toxic levels of it build up in the brain, blood, and other tissues.
Inheritance Pattern:
This disease is inherited through the autosomal recessive pattern, in which both copies of the gene in each cell have mutations. The parents each have a mutated gene, although they are generally only carriers and do not have the disease themselves. Most of the cases of Refsum disease comes from mutations in the PHYH gene. The PHYH gene is located on the short arm of the chromosome 10, at position 13, which is shown here.
The molecular location of the exact gene is on base pairs 13,319,795 to 13,342,129. The normal function of this gene is to provide instructions for making an enzyme called phytanoyl-coenzyme A (CoA) hydroxylase. The enzyme is what makes the peroxisomes--sac-like compartments that break down substances like fatty acids and toxic compounds--able to work. Phytanic acid is one of the fatty acids that the enzyme helps break down. Without that enzyme, the phytanic acid found mostly in meat and dairy food products, cannot be broken down and so it builds up in muscles and tissue.
Symptoms:
There are many symptoms of this disease, even though the disease itself is not very common, with less than 200,000 known cases as of 2010. Symptoms of Refsum's normally don't appear until the person reaches 20, although all symptoms might not appear until age 50. Initially, the symptoms start with retinitis pigmentosa--when the retina in your eye starts to degenerate, affecting night vision and peripheral vision, and can lead to blindness. Then peripheral polyneuropathy may occur--a dysfunction of the nerves outs
Treatment/Prognosis:
The prognosis of this disease varies very dramatically. There is a dietary regimen (consuming less than 10 mg/day of foods high in phytanic acid) that can cause the nerve response to improve, and cause the neurological symptoms to stop. Weakness and scaliness can also improve. The diet avoids beef, lamb, milk, full cream, butter, and cheese--all foods with a high concentration of phytanic acid. It is important to try and maintain your weight when you have this disease, because loss of weight can release stored aid that was in fat tissues, causing the symptoms to become worse. Before the dietary regimen was established, more than half of patients died before they turned 30. Now, very few patients have died so young. Plasmapheresis (replacement of plasma) is another treatment that may help ease symptoms. Without treatment, ARD can cause death because of heartbeat abnormalities.
There are a few support groups for Refsum's disease, the most popular being in Illinois. The contact information is listed below.
2304 Highland Drive
Sycamore, IL 60178
office@ulf.org
http://www.ulf.org
Tel: 815-895-3211 800-728-5483
Fax: 815-895-2432
Incidence/Frequency:
Refsum's disease is considered a rare disease by the Office of Rare Diseases of the National Institutes of Health, because it affects less than 200,000 people in the US. Orphanet--the European version of ORDNIH--considers this disease rare because only one out of 2,000 people have it. There is not a certain group of people that are more susceptable to it, although Refsum's is a recessive autosomal disease.
Works Cited:
Refsum Disease Information Page: NINDS. February 2007. National Institute of Neurological Disorders and Stroke. 12 April 2010 <http://www.ninds.nih.gov/disorders/refsum/refsum.htm>.
Refsum disease. January 2010. Genetics Home Reference. 12 April 2010 <http://ghr.nlm.nih.gov/condition=refsumdisease>.
Refsum. August 2008. United Leukodystrophy Foundation. 14 April 2010 <http://www.ulf.org/types/refsum.html>.
Prevalence and Incidence of Refsum Disease. April 2010. WrongDiagnosis. 18 April 2010 <http://www.wrongdiagnosis.com/r/refsum_disease/prevalence.htm>.
Discussion Questions:
1. Why is Refsum's disease considered rare IN EUROPE?
2. What is anosmia?
3. How is Refsum's inherited?